Electric battery.



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NEWCOMB K. CHANEY, 0F LAKEWOOD. OHIO, ASSIGNOR, )BY MESNE ASSIGNMENTS,T0

NATIONAL CARBON COMPANY, INC. A CORPORATION- OF NEW YORK.

ELECTRIC BATTERY.

No Drawing.

To all whom it may concern "Be it known that I, Nnwoolsm K. CTUQTEY. acitizen of the United States. residing at Lakewood. in" the county of(.uyahoga and State of Ohio, have invented a certain new and usefulImprovement in Electric Batteries. of which the following is a full.clear. and exact description.

This invention relates to electric batteries and is especiallyapplicable to so-called dry cells.

Dry cells. consist of a zinc can electrode in which is compacted anintimate mixture or mix as it is called, of carbon and manganeseperoxid, usually pyrolusite, more or less dampened with ammoniumchlori-d electrolyte. .The zinc-"can separated from the mix by abibulous lining, usually paper. which permits the electrolyte to reachit but prevents the insoluble constituents from passing through.

A common defect in dry cells is the corrosion of the zinc. regardless ofwhether the circuit is closed or not. I have made extensive experimentsto determine the cause of such corrosion, and find that it is chieflydue to impurities in the mix. I have discovered that iron salts andsulfide in the granular carbon and soluble material from the pyrolusite,are the constituents chiefly responsible! for the corrosive action. To

eliminate such materials I have leached them with the electrolyte to beused in the cell, and then, after washing, have incorporated thepurified materials in a dry cell. The open circuit voltage and shortcircuit current are increased by this treatment and shelf life testshave demonstrated that corrosion is very markedly decreased.

' Since the electrolyte would be an expen sive reagent to use forpurification of the mix, I use preferably a mineral acid such assulfuric, nitric or hydrochloric acid, to accomplish the same purpose.If one considers the iron sulfid as the harmful constituent, itsdeleterious efiect may be nullified by dissolving it from the mix or byoxidizing it to insoluble compounds.

In accordance Withthe-first process, nydrochloric or other acid may beused to react on the impurity in accordance with the fol* lowingequation 2- I Fes+eHc1=Feon+n s Tlhe ferrous chlcrid, being soluble, mayhe Specification of Letters Patent.

Patented Dec. 17, 1918.

Application filed June 7, 15 16, Serial No. 102,193.

washed out from the mix, and the hydrogen sulfid escapes as a 'gas.

in accordance with the second process the impurity is oxidized intoinsoluble and harmless ferric hydroxid and free sulfur. This oxidationmore readil' accomplished by first decomposing the ferrous sulfid withacid, and then applying the oxidizing agent. as air, chlorin, oxygencontaining compounds, etc. he essential transformations are summarizedin the reactions below In an electrolyte of ammonium chlorid and zincchlorid, such as is used in dry cells, any ferric salt will bedecomposed and precipitated as insoluble Fe(OH) Hence it is onlynecessary to getthe ferrous sulfid in solution and oxidize the iron tothe ferric conditionato' render it insoluble and harmless under normaldry cell conditions. Siroilarly, such hydrogen sulfid as'does not escapewill be changed to insoluble free sulfur it is not absolutely necessaryto use an acid solvent as described, since ferrous sullid is soluble inthe usual dry cell electrolyte of ammonium chlorid and zinc chlorid, andit will be oxidized by acting upon the cell mix with an oxidizing agent.Other solvents may also be used to dissolve the in purities preliminaryto acting upon them with oxidizing agents.

Instead of removing the iron sulfid by the process previously set forth,this can be accomplishedby spreading carbon and manganesc peroxidmoistened, for example. with dilute acid. in thin layers where it. willbe exposed to currents of warm air. The manganese peroxid being anoxidizing agen reacts on the acid mixture in the same way as the chlorinpreviously referred to. The purpose of spreading the mass in thin layersis to utilize the oxygen of the air as a further oxidizing means. Alsoto increase the action the materials may be heated to, say 108 (3., andthen the oxidation will be much more rapid.

Titrepurification likewise can he accomplished by passing soluble orgaseousfoxidizing agents around the carbon and manganese peroxidparticles until the sulfid is oxidized to harmless forms. As examples ofsuch agents I may mention potassium permanganate, hydrogen peroxid,bleaching powder, chlorin, 'iodin, etc.

The oxidizing materials should not be used in excess of the amountrequired by the reaction, or else the excess should be removed from themix before placing it in the cell, but this will be readily accomplishedby sufficient Washing With-Water after which the material should bedried.

' In case that hydrochloric acid isused to decompose the impurities, itis preferable to neutralize the surplus acid by adding zinc oxid insufiicient quantities to the cell mix rather than to remove it. Thehydrochloric acidwill react with the oxid to produce water and zinc'chlorid which are necessary ingredients of the cell.

Cells made up of purified pyrolusite and carbon show an increasedvoltage of about 0.1 to =2 volts, an increase of short circuit currentof about 4 to 6 amperes and a marked increase in shelf life.

The improvement in the characteristics of the dry cell, I believe, isdue to the removal of ferrous sulfid as previously mentioned and ofcertain impurities in the pyrolusite, although I have determined thatferrous and sulfid ions'each have a detrimental effect on the dry cell,regardless of the salt or material from which the ions may havedissoelated. I

Having described my invention, What I claim is:-

1. The process of treating a dry cell mix, which consists in etting itwith an acid solution to dissolve the ferrous sultid thercin, and then.washing-the mix with Water.

2. The process of treating a dry cell mix, which consists in Wetting itwith an acid to dissolve the ferrous sulfid, and then oxidizing theferrous ion to ferric ion insoluble inthe ammonium-chlorid, zinc-chloridelectrolyte of a dry cell.

3. The process of treating the carbon to be used in a dry cell mix,which consists in wetting it With-an acid, adding an oxidizing agent toit tooxidize the ferrous sulfid therein and adding zincoxid toneutralize any excess acid. H

4. The process of treating carbon to be used in a dry cell mix,-..whichconsists in mixing it With nianganesex peroxid, adding an acid theretoand freeing the mass of the surplus acid.

In testimony whereof, I hereunto affix my signature.

N. K. OHANEY.

